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[3.15] gh-149584: Fix excessive overhead in the Tachyon profiler regarding the cache behavior (GH-149649) (#150152)

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Miss Islington (bot) 2026-05-20 13:59:10 +02:00 • committed by GitHub
parent 7f29fa5032
commit 034c536d56
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12 changed files with 739 additions and 127 deletions
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101
Modules/_remote_debugging/frames.c
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@ -186,30 +186,16 @@ is_frame_valid(
return 1;
}
int
parse_frame_object(
static int
parse_frame_buffer(
RemoteUnwinderObject *unwinder,
PyObject** result,
uintptr_t address,
const char *frame,
uintptr_t* address_of_code_object,
uintptr_t* previous_frame
) {
char frame[SIZEOF_INTERP_FRAME];
*address_of_code_object = 0;
Py_ssize_t bytes_read = _Py_RemoteDebug_PagedReadRemoteMemory(
&unwinder->handle,
address,
SIZEOF_INTERP_FRAME,
frame
);
if (bytes_read < 0) {
set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to read interpreter frame");
return -1;
}
STATS_INC(unwinder, memory_reads);
STATS_ADD(unwinder, memory_bytes_read, SIZEOF_INTERP_FRAME);
*previous_frame = GET_MEMBER(uintptr_t, frame, unwinder->debug_offsets.interpreter_frame.previous);
uintptr_t code_object = GET_MEMBER_NO_TAG(uintptr_t, frame, unwinder->debug_offsets.interpreter_frame.executable);
int frame_valid = is_frame_valid(unwinder, (uintptr_t)frame, code_object);
@ -237,6 +223,31 @@ parse_frame_object(
return parse_code_object(unwinder, result, &code_ctx);
}
int
parse_frame_object(
RemoteUnwinderObject *unwinder,
PyObject** result,
uintptr_t address,
uintptr_t* address_of_code_object,
uintptr_t* previous_frame
) {
char frame[SIZEOF_INTERP_FRAME];
Py_ssize_t bytes_read = _Py_RemoteDebug_ReadRemoteMemory(
&unwinder->handle,
address,
SIZEOF_INTERP_FRAME,
frame
);
if (bytes_read < 0) {
set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to read interpreter frame");
return -1;
}
STATS_INC(unwinder, memory_reads);
STATS_ADD(unwinder, memory_bytes_read, SIZEOF_INTERP_FRAME);
return parse_frame_buffer(unwinder, result, frame, address_of_code_object, previous_frame);
}
int
parse_frame_from_chunks(
RemoteUnwinderObject *unwinder,
@ -312,15 +323,32 @@ process_frame_chain(
}
assert(frame_count <= MAX_FRAMES);
if (parse_frame_from_chunks(unwinder, &frame, frame_addr, &next_frame_addr, &stackpointer, ctx->chunks) < 0) {
if (ctx->chunks && ctx->chunks->count > 0) {
if (parse_frame_from_chunks(unwinder, &frame, frame_addr, &next_frame_addr, &stackpointer, ctx->chunks) == 0) {
goto parsed_frame;
}
PyErr_Clear();
}
{
uintptr_t address_of_code_object = 0;
if (parse_frame_object(unwinder, &frame, frame_addr, &address_of_code_object, &next_frame_addr) < 0) {
int parse_result;
if (ctx->prefetch.frame && ctx->prefetch.frame_addr == frame_addr) {
parse_result = parse_frame_buffer(
unwinder, &frame, ctx->prefetch.frame,
&address_of_code_object, &next_frame_addr);
}
else {
parse_result = parse_frame_object(
unwinder, &frame, frame_addr,
&address_of_code_object, &next_frame_addr);
}
if (parse_result < 0) {
set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to parse frame object in chain");
return -1;
}
}
parsed_frame:
// Skip first frame if requested (used for cache miss continuation)
if (ctx->skip_first_frame && frame_count == 1) {
Py_XDECREF(frame);
@ -501,41 +529,37 @@ try_full_cache_hit(
PyObject *current_frame = NULL;
uintptr_t code_object_addr = 0;
uintptr_t previous_frame = 0;
int parse_result = parse_frame_object(unwinder, &current_frame, ctx->frame_addr,
int parse_result;
if (ctx->prefetch.frame && ctx->prefetch.frame_addr == ctx->frame_addr) {
parse_result = parse_frame_buffer(unwinder, &current_frame,
ctx->prefetch.frame,
&code_object_addr, &previous_frame);
}
else {
parse_result = parse_frame_object(unwinder, &current_frame, ctx->frame_addr,
&code_object_addr, &previous_frame);
}
if (parse_result < 0) {
return -1;
}
Py_ssize_t cached_size = PyList_GET_SIZE(entry->frame_list);
PyObject *parent_slice = NULL;
if (cached_size > 1) {
parent_slice = PyList_GetSlice(entry->frame_list, 1, cached_size);
if (!parent_slice) {
Py_XDECREF(current_frame);
return -1;
}
}
if (current_frame != NULL) {
if (PyList_Append(ctx->frame_info, current_frame) < 0) {
Py_DECREF(current_frame);
Py_XDECREF(parent_slice);
return -1;
}
Py_DECREF(current_frame);
STATS_ADD(unwinder, frames_read_from_memory, 1);
}
if (parent_slice) {
Py_ssize_t cur_size = PyList_GET_SIZE(ctx->frame_info);
int result = PyList_SetSlice(ctx->frame_info, cur_size, cur_size, parent_slice);
Py_DECREF(parent_slice);
if (result < 0) {
Py_ssize_t cached_size = PyList_GET_SIZE(entry->frame_list);
for (Py_ssize_t i = 1; i < cached_size; i++) {
PyObject *cached_frame = PyList_GET_ITEM(entry->frame_list, i);
if (PyList_Append(ctx->frame_info, cached_frame) < 0) {
return -1;
}
STATS_ADD(unwinder, frames_read_from_cache, cached_size - 1);
}
STATS_ADD(unwinder, frames_read_from_cache, cached_size > 1 ? cached_size - 1 : 0);
STATS_INC(unwinder, frame_cache_hits);
return 1;
@ -606,7 +630,8 @@ collect_frames_with_cache(
}
if (frame_cache_store(unwinder, thread_id, ctx->frame_info, ctx->frame_addrs, ctx->num_addrs,
ctx->base_frame_addr, ctx->last_frame_visited) < 0) {
ctx->thread_state_addr, ctx->base_frame_addr,
ctx->last_frame_visited) < 0) {
return -1;
}